Golf club head

ABSTRACT

In one aspect, the invention provides a face for a golf club head. In one embodiment, the face includes an upper portion and a lower portion, wherein the lower portion has a lower toe portion located towards the toe of the golf club head, a lower heel portion located towards the heel of the golf club head, and a center portion extending from the lower toe portion to the lower heel portion, wherein the lower toe portion and the lower heel portion have a first substantially uniform thickness, the center portion and the upper portion have a second substantially uniform thickness, the second substantially uniform thickness is greater than the first substantially uniform thickness, the first substantially uniform thickness is in a range of about 0.055 inch to about 0.09 inch, and the second substantially uniform thickness is in a range of about 0.070 inch to about 0.13 inch.

This application is a continuation of U.S. patent application Ser. No.11/093,290, filed Mar. 30, 2005, which is a continuation-in-part of U.S.patent application Ser. No. 10/442,264, filed May 21, 2003 (now U.S.Pat. No. 7,131,912), which is a continuation-in-part of U.S. patentapplication Ser. No. 10/188,808, filed Jul. 5, 2002 (now U.S. Pat. No.6,659,885), which is a continuation-in-part of U.S. patent applicationSer. No. 10/062,234, filed Feb. 1, 2002 (now U.S. Pat. No. 6,659,884),the contents of the above-identified applications are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates, generally, to a golf club head and, morespecifically, to a golf club head with a face made from a titaniumalloy.

2. Discussion of the Background

When a golf club strikes a golf ball at rest, the ball is propelled athigh speed from the tee to the landing area. Thus, the kinetic energy ofthe moving club head is converted to kinetic energy in the moving golfball. The golf ball is only in contact with the face of the golf clubfor a few millionths of a second during impact and the distance achievedby the golf ball is a result of the combination of the initial velocityof the ball after impact, the launch angle, and the spin of the ball.Generally, however, the greater the velocity of the ball after impact,the farther the ball will travel.

The mass of the club head and the velocity at impact combine todetermine the initial velocity of the golf ball after impact. However,not all of the energy transferred to the ball is converted to kineticenergy and manifested as velocity. Some of the energy manifests as heatin the ball. Much of the kinetic energy lost as heat is related to theviscoelastic response of the ball during deformation.

The present invention is, in part, a result of the discovery that a golfclub face that deforms in preference to the ball will, unless it is alossy viscoelastomer, generally have a smaller hysteresis loop ondeformation and, therefore, result in less energy loss. In addition, ithas been found that it is preferable that the face of the club headdeform more than the remainder of the club head body. Thus, controllingdeformation of the golf club head in preference to deformation of thegolf ball will result in the golf ball traveling farther.

Generally, a golf club comprises a shaft portion, a head portion, and agrip portion. The part of the golf club head portion that comprises thehitting surface is referred to as the golf club “face”. Generally, agolf club face abuts or is adjacent to both a top wall (or crown) of theclub head and a bottom wall (or sole) of the club head.

Most “woods”, such as the driver and the fairway woods, are in the formof a hollow shell (or perhaps filled with foam), usually of metal.Because only the best and strongest golfers can effectively swing adriver head that weighs more than 220 grams, the maximum weight of theclub head is essentially a design constraint of the club head. Further,when the front side of the face of the golf club head strikes a golfball, extremely large impact forces are produced potentially causingcracking and/or material failure. Thus, the golf club face portion mustbe structurally adequate to withstand large repeated forces, such asthose associated with ball impact. In addition, a large club head faceis highly desirable because it strongly reduces the percentage of erranthits.

Thus, there are contrasting design considerations when designing a golfclub head—the desirability of a light club head, but with a large clubface and a club head that is durable enough to withstand repeatedstriking of the ball. One method of increasing the durability of theclub head is to add additional material (e.g., steel or titanium) tothicken the club face or to add ribs to the club face. However, thedesigner cannot simply add additional material to strengthen the faceindiscriminately because doing so also increases the overall weight ofthe club head, which is undesirable.

Prior golf club heads typically had relatively thick faces, which woulddeform only slightly at impact thereby causing the golf ball to deform,which created a significant loss of kinetic energy through conversion ofheat in the ball.

Thus, there is a need for a new golf club head with a club facestructure providing enhanced deformation for improving club performance,and that has structural integrity, thereby reducing cracking andmaterial failure, without otherwise adversely affecting clubperformance, look, and feel; and with limited affect on club headweight.

SUMMARY OF THE INVENTION

The primary object of the present invention is to overcome thedeficiencies of the prior art described above by providing a golf clubhead for hitting a golf ball farther.

In one aspect, the in invention provides a face for a golf club head. Inone embodiment, the face includes an upper portion and a lower portion,wherein the lower portion has a lower toe portion located towards thetoe of the golf club head, a lower heel portion located towards the heelof the golf club head, and a center portion extending from the lower toeportion to the lower heel portion, wherein the lower toe portion and thelower heel portion have a first substantially uniform thickness, thecenter portion and the upper portion have a second substantially uniformthickness, the second substantially uniform thickness is greater thanthe first substantially uniform thickness, the first substantiallyuniform thickness is in a range of about 0.055 inches to about 0.09inches, and the second substantially uniform thickness is in a range ofabout 0.070 inches to about 0.13 inches.

In another aspect, the invention provides a method for making awood-type golf club head. In one embodiment, the method includes:creating a face portion for the golf club head, wherein the step ofcreating the face portion comprises: obtaining a face blank from a sheetof metal consisting essentially of a titanium alloy, after obtaining theface blank, pressing the face blank into a die at about 70 tons psi, andafter pressing the face blank, heat treating the face blank to increasethe hardness of the face blank; and attaching the face portion to acrown and a sole of the golf club head after heating the face blank,wherein the sheet of metal from which the face blank is obtained has asubstantially uniform thickness of between about 0.075 inches and about0.13 inches so that the obtained face blank also has a substantiallyuniform thickness of between about 0.075 inches and about 0.13 inches.

Further features and advantages of the present invention, as well as thestructure and operation of various embodiments of the present invention,are described in detail below with reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and form partof the specification, illustrate various embodiments of the presentinvention and, together with the description, further serve to explainthe principles of the invention and to enable a person skilled in thepertinent art to make and use the invention. In the drawings, likereference numbers indicate identical or functionally similar elements.

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 is a front side view of an example embodiment of a club head ofthe present invention.

FIG. 2 is a top view of an example embodiment of a club head of thepresent invention.

FIG. 3 is a right side view of a club head of an example embodiment ofthe present invention.

FIG. 4 is a bottom view of an example embodiment of a club head of thepresent invention.

FIG. 5 is a cross-sectional view of an example embodiment of a club headof the present invention along line B-B of FIG. 4.

FIG. 6 is a cross-sectional view of an example embodiment of a club headof the present invention along line A-A of FIG. 2.

FIG. 7 depicts the vibrational response of an example embodiment of agolf club according to the present invention striking a golf ball.

FIGS. 8A-C illustrate an embodiment of the golf club face.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, for purposes of explanation and notlimitation, specific details are set forth, such as particularmaterials, shapes, methods of manufacture, casting processes, etc. inorder to provide a thorough understanding of the present invention.However, it will be apparent to one skilled in the art that the presentinvention may be practiced in other embodiments that depart from thesespecific details. Detailed descriptions of well-known casting processes,materials, golf club shapes, methods of manufacturing, devices,components, shafts, uses, techniques, and associated technologies, areomitted so as not to obscure the description of the present invention.

As shown in FIGS. 1-5, the present invention includes a sole 200, acrown 300, and a face portion 100, which together form club head 10.Referring specifically to FIG. 3, in the example embodiment of thepresent invention, the face portion 100 includes an upper portion 110,which is above the dashed line 145 shown in FIG. 3, and a lower portion120, which is below the dashed line 145 shown in FIG. 3. The horizontaland vertical lines of FIG. 3 identify portions of the face portion 100that have substantially the same thicknesses.

The lower portion 120 includes a lower toe portion 125 that is locatedtowards the toe of the club head, a lower heel portion 135 that ispositioned towards the heel of the club head, and a center portion 130between the lower toe portion 125 and lower heel portion 135. The lowertoe portion 125, which is generally oval in shape or more particularlyshaped in two inverted ellipses, or approximately like a football,includes an outer edge 126 that is towards the sole 200 and the toe 205of the club head and an inner edge 127 that is adjacent the centerportion 130. Likewise, the lower heel portion 135, which is generallyoval in shape, or more particularly shaped like a football, includes anouter edge 136 that is towards the sole 200 and heel 210 of the clubhead and an inner edge 137 that is adjacent the center portion 130.

The outer edge 126 of the lower toe portion 125 is slightly curved andis adapted to mate with the front edge of sole 200. The inner edge 127of the lower toe portion 125 is curved and in particular is generallyparabolic in shape in this example embodiment. In addition, the inneredge 127 extends from the upper portion 110 near the toe 205 to aboutone third of the distance to the heel 210 from the toe 205. The radiusof curvature of the inner edge 127 of the lower toe portion 125 is 0.75inches as the inner edge 127 approaches the center portion 130.

The outer edge 136 of the lower heel portion 135 is slightly curved andis adapted to mate with the front edge of sole 200. The inner edge 137of the lower heel portion 135 is curved and in particular is generallyparabolic in shape in this example embodiment. In addition, the inneredge 137 extends from the upper portion 110 near the heel 210 to aboutone third of the distance to the toe 205 from the heel 210. The radiusof curvature of the inner edge 137 of the lower heel portion 135 is 0.75inches as the inner edge 137 approaches the center portion 130.

The center portion 130 of lower portion 120 includes a heel side edgewhich coincides with inner edge 137, a bottom edge 133, a toe side edgewhich coincides with inner edge 127, and a top edge indicated by dashedline 145. The bottom edge 133 of the center portion is substantiallystraight and is 0.75 inches in length. The top edge of the centerportion 130 is integral with the upper portion 110 and the verticaldistance from the bottom edge 133 of the center portion 130 to the topcenter edge 146 of the upper portion 110 is 1.75 inches. As discussedabove, the parabolic shape of the edges provide increased strength,which greatly enhances the ability of the club face to deform more thanthe ball while maintaining structural integrity.

As is evident in the figures, the upper portion 110 extendssubstantially the entire length of the face 100 (i.e., substantially theentire distance from the heel to the toe). In addition, the upperportion 110 in this example embodiment extends from near the top center146 edge of the face 100 about one fourth to one half of the distancefrom the top center edge 146 to the bottom center edge 147 as indicatedby the dashed line 145 in FIG. 3. In this embodiment, the dashed line145 indicates the separation of the upper 110 and lower portions 120also coincides with the upper ends 129 and 139 of inner edges 127 and137, respectively. In alternate embodiments of the present invention,the upper portion 110 could extend a longer or shorter distance down theface 100. In this embodiment, the upper portion 110 extends nearly, butnot quite all the way, to the very top edge 146. The radius of curvatureof the upper end 129 of the upper portion 110 near the toe is 1.675inches.

Substantially all of the upper portion 110 and the lower center portion130 have substantially the same thicknesses. In this example embodiment,the thickness of lower center portion 130 and upper portion 110 may bein the range of about 0.050 inches to about 0.20 inches and ispreferably between about 0.050 inches and about 0.13 inches, and morepreferably between about 0.70 inches and about 0.125 inches. The lowertoe portion 125 and the lower heel portion 135 are also substantiallythe same thickness, which may be in the range of about 0.04 inches toabout 0.1 inches and is preferably between about 0.05 inches and about0.095 inches and most preferably about 0.090 inches.

As shown in FIGS. 3 and 5, in this embodiment a channel 140 is disposedaround the peripheral of the face 100. The channel 140 has a curvedsurface on the inside of the club head 10 (i.e., the back side of theface 100). In addition, the channel 140 is thinner than the otherportions of the face 100, thereby aiding in the deformation of the clubface 100. In this example embodiment, the channel 140 is approximately0.005 inches thinner than the thickness of the adjacent face portion100. The channel 140 is 0.055 inches wide and is preferably in the rangeof 0.0525 inches to 0.0575 inches and more preferably approximately0.055 inches thick at its thinnest point. Channels in other embodimentsof the present invention may extend only partially around the face, ornot at all, and may be other thicknesses.

The present invention also includes the removal of conventional scorelines in the center of the face where the face is thickest, in a shapethat profiles the parabolic shape. More specifically, the face portion100 includes a portion that has no score lines that is shapedsubstantially as an inverted triangle (i.e., base at the top) with atruncated apex (i.e., connected points 129, 139 with the respectivecorners of the lower center portion 130 as shown in FIG. 3). The scorelines on the outside of the face portion 100 end outside the internalparabolic shaped inner edges 137, 127 of the lower heel portion 135 andlower toe portion 125. The effect is to further strengthen the hittingarea of the face and to further improve durability. Alternateembodiments of the present invention could include score lines over partor all of the face.

As shown in FIG. 4, the sole 200 of the club head 10 includes a ridgeacross the sole 200 that produces a center rail 203 from back to frontwith a parabolic rise towards the face 100 of the club. The parabolicrise (indicated by the arrows labeled C in FIG. 4) on the sole 200provides additional lateral strength to the club head, without addingthickness to the sole 200 while still permitting the sole 200 to bend atimpact with a golf ball on the face. The center rail 203 also aids thegolfer when setting up to strike the ball and assists the golfer ingetting the ball airborne. Thus, the center rail 203 reduces frictionshould the club hit the ground while swinging so that the club may beused as a fairway wood. The wall thickness of the sole 200 is 0.035inches and the radius of curvature of the parabolic rise is 0.5 inches.The center rail is approximately 1.09 inches wide at its narrowestpoint.

As shown in FIG. 2, the crown 300 includes a center ridge 303 across thecrown 300 from back to front with a parabolic rise towards the face 100of the club. The parabolic rise (indicated by the arrows labeled D inFIG. 2) on the crown 300 provides additional lateral strength to theclub head, without adding thickness to the crown 300 while stillpermitting the crown 300 to bend at impact. The center ridge 303 alsoprovides a visual aid to the golfer when setting up to strike the ball.The wall thickness of the crown 300 is 0.035 inches and the radius ofcurvature of the parabolic rise is 1.150 inches. The center ridge 303 isapproximately 0.7 inches wide at the rear of the club and is 3.4 incheswide towards the front of the club head.

As discussed above, the parabolic rise in the sole 200 and crown 300provides increased strength, which greatly enhances the ability of theclub face to deform more than the ball and to maintain structuralintegrity.

It is also preferable that the wall thickness of the sole 200 and crown300 vary, being slightly thicker toward the heel. The varying thicknessmoves the center of gravity toward the heel, which improves performanceby building in a hook bias thereby assisting the golfer in pronating theclub head as the club approaches the ball during the swing. In thisexample embodiment, the crown and sole vary from about 0.035 inches atthe toe to about 0.040 inches at the heel.

In one method of making the golf club head 10, the crown is cast withthe face and a small lip that extends rearward approximately 0.25 inchesfrom the face. The sole is then welded to the crown and to the lipextending from the face as shown by the jagged line of FIG. 5. By thismanufacturing procedure, the thickness of the connection of the face tothe crown can be accurately controlled. In this embodiment, the clubhead is formed of steel, but other embodiments may use alternativematerials such as titanium, Teflon, or like materials, and differentportions of the club head may be made of different materials. The faceof the steel club head may be polished (shiny) so that the impact of theball with the club head results in a mark where the ball impacted theclub head face. Thus, the club head face provides feedback to the golferregarding where on the club face the golfer is striking the ball. Thepolished nature of the club face allows the golfer to repeatedly get thefeedback by periodically wiping the club face clean.

In the present example embodiment, the shaft is attached to the clubhead 10 in any conventional fashion. The shaft may be any shaft suitablefor the golfer such as Penley® or Graphite Design® shafts. The hoselneck protrudes 0.500 inch out of the heel end of the crown. The totalhosel depth is 1.500 inch from the top of the hosel to the seat withinthe club head, so the hosel is one inch into the club head. The totaldistance from the tip of the hosel to the sole is 3.150 inch.

The club of the above example is USGA compliant with a club head that is420 cubic centimeters and weighs 200 g. The weight of the sole plate is46 g. Tables 1 and 2 below provide a number of parameters for golf clubshaving 9.5 and 11 degree lofts, respectively.

TABLE 1 RH 9.5 RH 11 LOFT ANGLE  9.5 11.0 LIE ANGLE 55.0 55.0 FACE ANGLE0.0 closed 1.0 closed BULGE RADIUS 11″ R inch 11″ R inch ROLL RADIUS 11″R inch 11″ R inch BOUNCE METRIC 1  1  FRONT TO BACK 20″ R inch 20″ Rinch HEEL TO TOE  6″ R inch  6″ R inch

TABLE 2 RH 9.5 RH 11 INSIDE 0.348 0.348 DIAMETER 0.490 0.490 OUTSIDEDIAMETER HOSEL 1.500 1.500 DEPTH CHAMFER SIZE .032 R .080 Depth .032 R.080 Depth HOSEL PAINT 0.500 0.500 TAPE LINE BOTTOM HOSEL TRUE 0.2500.250 HOLE DIAM. WALL THICKNESS 0.050 0.050

The outside diameter of the hosel is 0.500 inch and the inside diameteris 0.348 inch.

In a preferred embodiment of making the golf club head 10, the crown 300and sole 200 are cast as one seamless and joined piece to form a castbody with a face opening that is only two millimeters larger than aprecision formed face portion 100. The face portion 100 is then attachedonto the cast body by, for example, welding or the like. The faceportion 100 may be polished after welding and then the body may bepainted. Next, a shaft may be fitted and gripped.

According to one embodiment, a method of making the face portion 100includes forming the face portion from sheet metal (e.g., steel,titanium, titanium alloy, etc. sheet metal) formulated to provide veryhigh strength and durability. In one embodiment the thickness of thesheet metal is substantially uniform and is between about 0.05 and 0.2inches. In some embodiments, the sheet metal may be 275 steel, which isstronger than 17-5 stainless steel, may be used. A face portion formedfrom 275 steel can be manufactured with extreme accuracy andrepeatability and will not lose durability over time.

In one embodiment, the face portion may be made from or include amaterial having the following properties: ultimate strength (Mpa) ofabout 1100-1250; yield strength (Mpa) of about 1000; elongation (%) ofabout 10; stress, time and temperature to produce 0.2% elongation(creep) of about 320 Mpa/100 hours/400 degrees centigrade; hardness(brinell) of about 285; beta transus (C) of about 840-880; density(g/cc) of about 4.6; modulus of elasticity (tension Gpa) of about 110;and specific heat (W/m*K) at room temperature of about 8.32. Onematerial that has these or many of these properties is a Russiantitanium alloy referred to herein as “BT-22.” In one embodiment, BT-22preferably includes or consists essentially of about 4.4 to 5.7 percentweight aluminum, 4.0 to 5.5 percent weight molybdenum, 4.0 to 5.5percent weight vanadium, 0.5 to 1.5 percent weight chromium and 0.5 to1.5 percent weight iron and the remainder being substantially titanium.Other formulations of BT-22 are contemplated. BT-22 preferably has amaximum of 0.1 percent weight carbon, 0.15 percent weight silicon, 0.18percent weight oxygen, 0.05 percent weight nitrogen and 0.015 percentweight hydrogen. A face plate made from sheet metal consisting of oressentially of BT-22 produces excellent results. BT-22 can be obtainedfrom Cronos Ltd., Moscow, Russia.

Based on the specified size and curvature of the desired face portion100, the sheet metal is laser cut, thereby forming a laser cut blank.The laser cut blank is then precision machined to provide the variablethickness in the face design as described herein. The scorelines (e.g.,grooves), if any, may be engraved onto the outside of the laser cutblank using, for example, 70,000 RPM high speed spindles. The machinedblank is then pressed into a die at, for example, at least about 50 tonspsi (preferably at least about 60 tons psi, and most preferably at leastabout 70 tons psi), to form the desired face portion 100. The pressureapplied to the machined blank forms the blank into a precise faceportion with exact bulge and roll characteristics according tospecifications described herein. The face portion 100 may then be heattreated at high temperature to raise the Rockwell Hardness of the faceportion to 45 or higher. Once completed the process yields a very highstrength precision formed face portion.

FIG. 7 depicts the vibrational response of a golf club embodying anembodiment of the present invention striking a golf ball, which relatesto the club's fundamental frequency. The resultant golf club provides ahigher fundamental frequency than existing club heads. The combinationof high fundamental frequency and greater deformation of the club headreduces the energy lost as heat in the golf ball (and club) at impact.

The club heads described herein are suitable for use as a driver orwood. The size, weight, and angle on the face of the club head of thepresent invention may vary depending on the use of the club head in, forexample, a driver, 3-wood, 5-wood, etc. For example, the club head ofthe present invention used in a 3-wood is about ⅔ the size of the clubhead used in a driver, and the angle on the face is about 13 degrees.The angle on the face of the club head of the present invention used in,for example, a 5-wood is about 17 degrees. The volume of a club head ofthe present invention used in a driver may be, for example, about 280cc, or may be about 420 cc or 460 cc in an oversized or jumbo typedriver made of titanium, for example.

While the above example embodiment includes a center portion 130 thathas two curved sides that abut lower heel portion 135 and lower toeportion 125, in an alternative embodiment the sides could be straight sothat inner edges 137 and 127 are straight. In addition, while thetransition from the thickness of the center portion to the thickness ofthe lower toe portion 125 and lower heel portion 135 (which define edges127 and 137, respectively) is abrupt in the above example embodiments,in an alternate embodiment the transition could be more gradual (forexample, transitioning over a half inch, three eighths of an inch,quarter inch, eighth inch, or sixteenth of an inch).

This alternative embodiment is illustrated in FIGS. 8A-8C. FIG. 8Aillustrates a golf club face 800. As shown in FIG. 8A, golf club face800 includes three non-overlapping regions: (1) region A; (2) region B1;and (3) region B2. Additionally, face 800 may include a region C1, whichis positioned between regions A and B1, and a region C2, which islocated between regions A and B2.

In the embodiment where face 800 includes region C1, region B1 isbounded by a portion of the edge of face 800 and a line 802, otherwiseit is bounded by a line 832 and the portion of the edge of face 800.Line 802 extends from a first point 803 located at the edge of face 800and below an upper left-hand corner 810 of face 800 to a second point804 located at the edge of face 800 to the left of a bottom-center-edgepoint 850. In one embodiment, second point 804 is about 10 mm to theleft of bottom-center-edge point 850, but other distances arecontemplated. Preferably, line 802 is a curved line in the shape of aparabola, but the line may also be straight.

Similarly, in the embodiment where face 800 includes region C2, regionB2 is bounded by a portion of the edge of face 800 and a line 806,otherwise it is bounded by a line 836 and the portion of the edge offace 800. Line 806 extends from a first point 807 located at the edge offace 800 below an upper right-hand corner 811 of face 800 to a secondpoint 808 located at the edge of face 800 to the right ofbottom-center-edge point 850. In one embodiment, second point 808 isabout 10 mm to the right of bottom-center-edge point 850, but otherdistances are contemplated. Preferably, line 806 is a curved line in theshape of a parabola, but the line may also be straight.

Region A encompasses all or substantially all of the remaining portionof face 800. Conceptually, region A can be divided along a line 890 thatextends from a point 833 to a point 837. Line 890 bisects region A intoa top region D1 and a bottom-center region D2. As shown in FIG. 8A, topregion D1 can have a width of about 16.5 mm and can extend lengthwisefrom the upper-right-hand corner 811 to the upper-left-hand corner 810.In other embodiments, the width of top region D1 can range between aboutone quarter and one half of the width of the face (e.g., between about10 mm and 25 mm, in the embodiment shown in FIG. 8A).

A region C1 and a region C2 may be positioned between regions A and B1and A and B2, respectively. In the embodiment shown in FIG. 8A, regionC1 is bounded by line 802 and line 832, and region C2 is bounded by line806 and line 836. Line 832 extends from a first point 833 located at theedge of face 800 and located between point 803 the upper left-handcorner 810 of face 800 to a second point 834 located at the edge of face800 and located between point 804 and bottom-center-edge point 850. Line836 extends from a first point 837 located at the edge of face 800 andlocated between point 807 the upper right-hand corner 811 of face 800 toa second point 838 located at the edge of face 800 and located betweenpoint 808 and bottom-center-edge point 850. Preferably, lines 832 and836 are curved lines, each in the shape of a parabola, but the lines mayalso be straight.

As shown in FIG. 8A, both point 833 and point 837 have the same verticaldistance from a top-center-edge point 851. In the embodiment shown, thisvertical distance is about 16.5 mm. In alternative embodiments, it iscontemplated that this vertical distance can be anywhere between aboutone quarter and one half of the width of the face, which, in theembodiment shown, is about 47 mm.

As discussed above with respect to other embodiments, regions D1, D2,B1, and B2 each may have a substantially uniform thickness. Preferably,regions D1 and D2 have the same thickness and regions B1 and B2 have thesame thickness which is thinner than the thickness of regions D1 and D2.This feature is illustrated in FIG. 8B.

FIGS. 8B and 8C show that, unlike regions A and B, regions C1 and C2 donot have a substantially uniform thickness. That is, region C1 providesa gradual transition region between regions A and B1 so that face 800does not have an abrupt change in thickness between regions A and B1.Likewise, region C2 provides a gradual transition region between regionsA and B2. FIG. 8C also shows that region C1 has a preferred width ofabout 2.5 mm and a preferred radius of curvature of about 8.4 mm, butother widths and curvatures are contemplated.

While the above example embodiment includes a center portion 130 thathas a substantially flat lower edge, alternate embodiments could includea rounded bottom edge or a pointed lower end. In addition, while thethickness of the lower toe portion 125 and lower heel portion 135 arethe same in the above example embodiment, in an alternate embodimentthey could be different with the lower heel portion 135 being thickerthan the lower toe portion 125 or vice versa.

The foregoing has described the principles, embodiments, and modes ofoperation of the present invention. However, the invention should not beconstrued as being limited to the particular embodiments describedabove, as they should be regarded as being illustrative and not asrestrictive. It should be appreciated that variations may be made inthose embodiments by those skilled in the art without departing from thescope of the present invention.

While a preferred embodiment of the present invention has been describedabove, it should be understood that it has been presented by way ofexample only, and not limitation. Thus, the breadth and scope of thepresent invention should not be limited by the above described exemplaryembodiment.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

What is claimed is:
 1. A method for making a wood-type golf club head,comprising: creating a face portion for the golf club head, wherein thestep of creating the face portion comprises: obtaining a blank from apiece of sheet metal consisting essentially of a titanium alloy, afterobtaining the blank, exposing the blank to a pressure of about 70 tonspsi, and heat treating the blank to increase the hardness of the blank;and attaching the face portion to a crown and a sole of the golf clubhead after heat treating the blank, wherein the piece of sheet metalfrom which the blank is obtained has a substantially uniform thickness.2. The method of claim 1, wherein the thickness of the piece of sheetmetal is between about 0.075 inch and about 0.13 inch so that theobtained blank also has a substantially uniform thickness of betweenabout 0.075 inch and about 0.13 inch.
 3. The method of claim 1, furthercomprising the step of casting the crown and sole as one seamless andjoined piece to form a cast body.
 4. The method of claim 1, wherein theface is attached to the crown and the sole by welding.
 5. The method ofclaim 1, wherein the heat treatment raises the Rockwell Hardness to atleast about
 45. 6. The method of claim 1, further comprising the step ofmachining the blank to provide a variable thickness in the face blank.7. The method of claim 1, wherein the step of obtaining the blankcomprises laser cuffing the sheet of metal.
 8. The method of claim 1,wherein the face portion comprises an upper portion, a lower portion, atoe side edge, a heel side edge, and a bottom edge, the lower portionhaving a lower toe portion located towards a toe of the golf club head,a lower heel portion located towards a heel of the golf club head, and acenter portion located between the lower toe portion and the lower heelportion, the lower toe portion and the lower heel portion each (a) beingsubstantially oval in shape, (b) having a side that is generallyparabolic in shape, and (c) having a first substantially uniformthickness, the center portion and the upper portion having a secondsubstantially uniform thickness, the second thickness being greater thanthe first thickness.
 9. The method of claim 8, wherein: the parabolicside of the lower toe portion extends from a point substantially on thetoe side edge of the face to a first point substantially on the bottomedge of the face; the parabolic side of the lower heel portion extendsfrom a point substantially on the heel side edge of the face to a secondpoint substantially on the bottom edge; the center portion has an upperside that coincides with at least a portion of a lower side of the upperportion.
 10. The method of claim 1, wherein the face consists of anupper portion and lower portion, wherein the lower portion consists of alower toe portion located toward the toe of the golf club head, a lowerheel portion located toward the heel of the golf club head, a centerportion located between the lower toe portion and the lower heelportion, a first transition region disposed between the lower toeportion and the center portion, and a second transition region disposedbetween the lower heel portion and the center portion, the lower toeportion and the lower heel portion having a substantially paraboliccurved side and having a uniform thickness in a range of about 0.055inch to about 0.09 inch, and the center portion and the upper portionhave a uniform thickness in a range of about 0.07 inch to about 0.13inch, wherein the transition portions have a non-uniform thickness sothat there is a smooth transition between the lower toe portion and thecenter portion and between the lower heel portion and the centerportion.
 11. The method of claim 1, wherein the face portion comprises:an upper portion, a lower portion, a first side edge, a second sideedge, a top center edge, and a bottom center edge, wherein, the lowerportion has a lower toe portion located towards the toe of the golf clubhead, a lower heel portion located towards the heel of the golf clubhead, and a center portion disposed between the lower toe portion to thelower heel portion, wherein the upper portion extends from the topcenter edge a distance in a range of about one fourth to one half of thedistance from the top center edge to the bottom center edge, the upperportion extends substantially the entire length of the face portion, thelower toe portion and the lower heel portion having a firstsubstantially uniform thickness, the center portion and the upperportion have a second substantially uniform thickness, and the secondsubstantially uniform thickness is greater than the first substantiallyuniform thickness.
 12. The method of claim 11, wherein the firstsubstantially uniform thickness is in a range of about 0.070 inch toabout 0.13 inch and the second substantially uniform thickness is in arange of about 0.055 inch to about 0.09 inch.
 13. The method of claim 1,further comprising the step of polishing the face portion so that theface portion is shiny so that impact of a ball with the face portionresults in a mark where the ball impacted the face portion.
 14. Awood-type golf club head made according to the method of claim
 12. 15. Awood-type golf club head made according to the method of claim
 1. 16. Awood-type golf club head, said wood-type golf club head comprising aface having (1) an upper portion, (2) a lower portion, (3) a toe sideedge, (4) a heel side edge, and (4) a bottom edge, said lower portionhaving (a) a lower toe portion located towards a toe of the golf clubhead, (b) a lower heel portion located towards a heel of the golf clubhead, and a (c) center portion located between the lower toe portion andthe lower heel portion, said lower toe portion and said lower heelportion each (a) being substantially oval in shape, (b) having a sidethat is generally parabolic in shape, and (c) having a firstsubstantially uniform thickness, said center portion and said upperportion having a second substantially uniform thickness, said secondthickness being thicker than said first thickness, wherein saidparabolic side of the lower toe portion extends from a pointsubstantially on the toe side edge of the face to a first pointsubstantially on the bottom edge of the face; said parabolic side of thelower heel portion extends from a point substantially on the heel sideedge of the face to a second point substantially on the bottom edge; andsaid center portion has (1) a heel side that coincides with the side ofthe lower heel portion that is generally parabolic in shape, (2) a toeside that coincides with the side of the lower toe portion that isgenerally parabolic in shape, and (3) an upper side that coincides withat least a portion of a lower side of the upper portion.
 17. Thewood-type golf club head of claim 16, wherein the width of said upperportion is between about ¼ and ½ of the width of the face and the lengthof the upper portion is about equal to the length of the face.
 18. Agolf club comprising the golf club head of claim
 16. 19. The wood-typegolf club head of claim 16, wherein the face has a side that is shinysuch that impact of a ball with the face results in a mark where theball impacted the face.